대답:
버텍스: (2.5, -15.75)
대칭축: x = 2.5
설명:
#f (x) = 3x ^ 2-15x + 3 #
#f (x) = 3 x ^ 2-5x + 3 #
#f (x) = 3 (x-5 / 2) ^ 2-25 / 4 + 3 #
#f (x) = 3 (x-5 / 2) ^ 2-75 / 4 + 3 #
#f (x) = 3 (x-5 / 2) ^ 2-15 3 / 4 #
# x-5 / 2 = 0 #
# x = 5 / 2 #
#f (x) = 3 (0) ^ 2 -15 3 / 4 #
#f (x) = - 15 3 / 4 #
#therefore vertex: (5/2, -15 3/4) #
#therefore "대칭축": x = 5 / 2 #